function [ status, code ] = mx_eyelink_get_tracker_version( )
%MX_EYE_LINK_GET_TRACKER_VERSION After connection, determines if the 
% connected tracker is an EyeLink I or II.
%
% Remarks:
% For the EyeLink II tracker, it can optionally retrieve the tracker software
% version.
% 
% Returns:
% 0 if not connected, 1 for EyeLink I, 2 for EyeLink II. This will be 
% "EYELINK I" or "EYELINK II x.xx", where "x.xx" is the software version.
%
%----------------------------------------------------------------------------
% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com